The present invention relates to industrial processing plants. More particularly, the present invention relates to transmitters and other transducers used to measure process variables in such plants.
Transducers of many types, for example, pressure transmitters, are manufactured in an increasing number of variations to meet the differing needs of many different kinds of plant control systems. There are variations in the amount of control function embedded in the transducer, variations in plant communication protocol, and also variations in the amount of data displayed and operator controls in the transducer.
Increasingly, transducers are manufactured in variations that transduce multiple variables of different types. Model 3095MV Multivariable Flow Transmitter manufactured by Rosemount Inc. of Eden Prairie, Minnesota, for example, senses both a volumetric flow and a temperature and provides a transmitter output representing mass flow rate. Transducers are also manufactured that sense multiple variables of the same type, such as a differential pressure transmitter that senses two pressures and provides a transmitter output representative of flow or liquid level. With some of these multiple variable transducers, circuits in multiple transducer housing spaced a short distance apart are electrically connected to complete the transducer.
There is a desire to provide each such multiple variable transducer with many optional features so that it can be adjusted in the field to fit a wide variety of plant installation requirements. Electrical power limitations, size and cost constraints, and ease-of-installation needs, however, severely limit the number of variations that can be provided in a single transducer.
An improved modular transducer assembly is disclosed. Modules in the transducer assembly are connected by an improved transducer intraconnection bus.
The intraconnection bus senses which transducer components have been intraconnected in a particular installation and then specially adapts the method of communication used on the intraconnection bus to operate with the particular transducer components in that particular installation.
The transducer assembly includes only a limited number of transducer components, or modules, chosen from a larger number of interchangeable types of transducer components. The intraconnected transducer components include at least one transducer component of a type having a functional variation selected from the group of plant communication protocol, fluid variable, operator control, embedded control and display functional variations.
One intraconnected transducer component is a sensor module having a fluid variable sensor and an adaptation circuit that, during an adaptation interval, exchanges type data over the transducer intraconnection bus. At the end of the adaptation interval, the adaptation circuit stores data representing a selected method of communication that is adaptable to the types connected.
The sensor module has a communication circuit that, during an operational interval following the adaptation interval, uses the selected method of communication.